https://www.summitracing.com/parts/f...BoCILQQAvD_BwE
Not sure why you'd need a spacer. This Ford Motorsports thermostat housing for 289, 302, 351 is pretty tall. Not a show piece, through. It's made of unpolished
zinc alloy. At $59.99, it's a great deal.
I'd call Summit and and see if it'll fit your application. (800) 230-3030